Recently, miniaturization of electronic devices such as a desktop personal computer, a mobile personal computer, and a server is being promoted. Electronic components such as a central processing unit (CPU) used in these electronic devices generate heat as they are operated.
When the temperature of the electronic components such as the CPU exceeds a permissible upper temperature limit, a problem such as a failure, malfunction, or a decrease in processing capability is caused. Thus, a means for cooling an electronic component that generates a large amount of heat is required.
An air-cooling method and a water-cooling method are used to cool the electronic components. In the case of cooling an electronic component that generates a large amount of heat, the water-cooling method is often employed. Hereinafter, the electronic component that generates a large amount of heat will be referred to as a heat generation component.
In a water-cooling type cooling apparatus, a heat receiving part is mounted on the heat generation component, and a heat exchanger and a cooling fan are arranged at a location that is spaced away from the heat receiving part, and the heat receiving part and the heat exchanger are connected to each other via a pipe. The heat receiving part is provided with a flow path through which the cooling water flows. By circulating the cooling water between the heat receiving part and the heat exchanger, the heat generated from the heat generation component is transferred to the heat exchanger, and then is dissipated from the heat exchanger to the atmosphere. The heat exchanger is provided with a plurality of heat radiation fins along a flow path through which a refrigerant flows.
Further, herein, water or other fluids (refrigerant) that are used for transferring heat from the heat receiving part to the heat exchanger will be referred to as “cooling water.”
With the miniaturization of the electronic device, miniaturization is also required for the heat exchanger mounted in the electronic device. However, when the size of the heat exchanger is merely reduced, the flow path of the cooling water is narrowed so that a pressure loss increases and the flow rate of the cooling water flowing in the heat exchanger and the heat receiving part is reduced. Consequently, the heat exchange efficiency of the heat exchanger is lowered so that the heat generation component may not be sufficiently cooled.
The followings are a reference documents.
[Document 1] Japanese Laid-Open Patent Publication No. 2014-053507,
[Document 2] Japanese Laid-Open Patent Publication No. 2014-052142,
[Document 3] Japanese Examined Utility Model Registration Application Publication No. 02-005326 and
[Document 4] Japanese Laid-Open Patent Publication No. 11-230638.